Fire detection apparatus of the compensation type



J1me 1965 mswso NuMM-Am. 3,188,434

FIRE maximum-mm APEARMI'US 0E 74m: COMPENSATION TYPE Filed April 30, 195% 2. Sheets-Sheet 2 Infi 30 v 1144/ I my. 6

I Fixed-Temperature type themostat A Rate-of-Riae type I thermostat S P L INVENTOR.

- 3,188,434 FIRE DETECTION APPARATUS OF THE COMPENSATION TYPE Yoshiro Numayama, Kawasaki-shi,

Japan, assignor to Nippon Kasai Tanchiki Company Limited, Tokyo, Japan, a corporation of Japan Filed Apr. 30, 1963, Ser. No. 276,832 Claims priority, application Japan, Apr. 8, 1963, 38/2 944 1 Claim. of. 200-140 Kanagawa-ken,

fixed temperature type. The differential type is brought into operation in case the detector is maintained above the setting value of the rising rate of the temperature and detects sharply the sudden rising of the temperature due to any fire, however, when the rise in temperature is effected slowly, such-as in case of a fire of continuous smolding there is the danger that no alarm will be given. Also, in the fixed temperature type of the fire detector in which the alarm is operated only when a high temperature range has been reached which is above the setting temperature, a fire is detected near the setting temperature as far as the rise in tcmperautre is eifected slowly. It is well known, however, that in the fixed temperature type the detection of a fire upon sudden rise of the temperature is found to be delayed.

It is, therefore, one object of the present invention to provide a fire detection apparatus which avoids the draw back of the known apparatus.

It is another object of the present invention to provide a .fire detection apparatus which is capable of operatingthe differential temperature type and the fixed temperature United States Patent type, and which is operated during the low temperature for a sudden rise of the temperature, and in case of having a slow rise of the temperature, a detection of a fire is positively effected at a predetermined setting temperature.

It is another object of the present invention to provide a fire detection apparatus in which a detection speed of the apparatus is automatically regulated in response to the ambient temperature in, the location thereof, that is, a sensibility of the apparatus in the sunnner season in comparison with that in the winter season is made sharply in sensitivity and little or no error information due to the change of the ambient temperature is caused.

It is yet another object of the present invention to provide a fire detection apparatus in which the detection apparatus of the differential temperature type is combined with the operation mechanism of the fixed temperature type, so as to form a very simple construction having an accurate sensitiveness for both slow and sudden temperature rise.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is a sectional side View of a fire detection apparatus according to the present invention;

FIG. 2 is a section along the lines 2--2 of FIG. 1;

FIG. 3 is a bottom plan view of a detection part of the present invention;

FIG. 4 is a top plan view of the fire detection apparatus of the present invention;

FIG. 5 is a fragmentary section of the base plate and of the cover plate; and

FIG. 6 is a diagram depicting the characteristics explaining about a detection status according to the present invention.

Referring now to the drawings, and in particular to FIGS. 1 and 2, a heat receiving shell 1 is formed in a deep dish shape and a boundary plate 2 is attached inside of the heat receiving shell 1. The shell 1 and the plate 2 are made of a thin metal sheet having a high coefiicient of linear expansion, for example, by making the same of brass sheet. The boundary plate 2 is formed of a shallow dish shape and is fixed by fitting a flange 3 at its outer edge on a circumferential step 1 of the heat receiving shell 1. The bottom surface 4 of the boundary plate 2 has a recess, and a cylindrical wall 5 is formed centrally about the recess toward the inner surface of the heat receiving shell 1. The cylindrical wall 5 is closed at its lower end by means of a diaphragm 6.

Accordingly, the heat receiving chamber 7 is formed by the heat receiving shell 1, the boundary plate 2 and a diaphragm 6. The chamber 7 is only in communication with atmospheric air through a leak hole formed in a leak cylinder 8 standing on the recessed bottom 4 of the boundary plate 2.

A spring member 9 is secured to the surface 4 of the recessed boundary plate 2 by insulating it electrically to extend radially above the diaphragm 6. A pair of contacts 10 are provided in opposed direction to each other at the free end of the spring member 9 and at the center of the diaphragm 6, respectively. Also, in accordance with this embodiment, an operating member 12, flexed at its center portion upwardly, is fixed to extend diametrically above the contact 10 at the free end of the spring member 9 by fixing both ends of the operating member 12 on the top face of the recessed bottom 4 to extend across diametrically above the diaphragm 6. This operating member 12 is made of metal having a small coefficient of linear expansion, such as invar or super-invar, or the like.

vAt the upwardly bent part intermediate of the operating member 12, an adjusting screw 13 is threaded therein and directed toward the contact 10. The spring member 9 is always engaged resilienlty at its free end from the underside with the screw 13.

A base stand 14 having the form of a dish, is made of electrically insulating material, such as hard synthetic resin or Bakelite and the like. A groove 15 is formed on the bottom of the base stand 14 and an open circumferential edge of the heat receiving shell 1 and an open cir- V cumferential edge of the boundary plate 2 are so fitted in the groove 15, so as to adhere thereto by means of a binding agent. In this case, the leak cylinder 8 andthe head of the screw 13 are placed in bores 16 and 17, respectively, in the base stand 14. The leak cylinder 8 and the space between the contact 10 and the contact 11 can be adjusted through the bores 16 and 17, respectively.

Further, these bores 16 and 17 are covered by means of removable caps 16' and 17'. Projected parts 18 and 19 are arranged opposite each other diametrically on the base surface of the base stand 14.

Contact members 20 and 21 are, respectively, at their basic parts fixed together on the upper surfaces of the projected parts 18 and 19 with lugs 22 and 23 on the I bottom face of the base stand 14 by means of screws 18' inner face of the cover plate 25 diametrically opposite each other and are fixed on the under face of the cover 7 plate 25 only is rotated in clockwise direction, the clipshaped contact members 27 and 28 clip the contact members 219 and 21, respectively, so as to stop the cover at the desired position, whereby the upper open part of the base stand 14 is closed. Lead wires 31 and 32 in an electrical circuit of an alarm device 30 connected to an electrical source or comprising a battery 29 are conducted into the base stand 14 covered by the cover plate 25 through a central opening 33 formed in the cover plate 25, so as to finish the wiring by connecting them to the clip-shaped contact members 27 and 28, respectively, mounting screws are passed through mounting holes 34 and 35 (FIG. 4) formed in the cover plate 25 and then the present fire detector is fixed at a suitable located place.

Further, a drain hole 36 is provided for watercollected in the base stand 14 through the openings in the cover plate 25 or a mounting space between the cover plate 25 and the base stand 14. The drain hole 36 is opened at the outer side of the annular groove 15 for mounting the heat receiving shell 1, so as to avoid a short circuit of the clip-shaped contact members 27 and 28 by the collected water.

A projecting partition 37 is provided in diametrical direction on the face of the recessed bottom 4 of the base stand 14.

The projecting parts 18 and 19 are positioned at both sides, respectively, of the partition 37. Even when the The space between both contacts 10 and 11 is adjusted by means of the adjusting screw 13 as follows:

In the summer season, the operating member 12 is stretched by the expansion in heat of the heat receiving shell 1 and the boundary plate 2, and the contact 10 is lowered by the action of the adjusting screw 13 and consequently the above space in the summer reasonis narrower than that in the winter season.

For the above reason, a sensitivity between the summer season and the winter season is appreciably dilferent in magnitude.

The above difference in sensitivity has no dangerous effect in the detection of fire in the summer season in which many windows are opened and a sharp sensitivity is necessary, and also in the winter season having many windows closed, the sensitivity becomes dull so as to avoid an information error. V 0

,While I have disclosed one embodiment of the present invention, it is to be understood'that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claim.

drain of water through the drain hole 36 is not effected sufficiently, the clip-shaped contact members 27 and 28 are not short circuited until the water is collected over the partition beam 37.

The present invention constructed as above described, in the case of a sudden rise of the temperature, is the same as that of the prior diiferential type (a rate of rise type thermostat) and the heat receivingv shell 1 is suddenly heated so as to expand air in the chamber 7, and a part of the air escapes through the leak hole of the leak cylinder 8, however, since the increase of the inner pressure in the chamber 7, the diaphragm 6 is so expanded upwardly as shown in dotted lines in FIG. 1 as to close the contacts 11 and 10, whereby an alarm circuit is closed to produce an alarm by the alarm device 30.

However, in the case of a slow rise of the temperature, air in the chamber 7 is expanded in response to the rate of rise of the temperature, and the pressure is relieved to balance it through the leak cylinder 8 and as shown by dotted lines of FIG. 2, the diaphragm 6 is expanded according to the relieved balance pressure to raise the contact 11. At the same time as the above, the heat receiving shell 1 and the boundary plate 2 themselves expand by the absorbed heat to stretch the operating member 12 at both ends. Consequently, the operating member 12 is extended horizontally and the adjusting screw 13 acts to press down the free end of the spring member 9, so that the contact 10 is contacted with the raised contact 11, so

as to close the alarm circuit for generating an alarm.

By the rotation of the adjusting screw 13, the position of the contact 10 may be moved up and down, to adjust the space between the contact 10 and the contact 11, an 7 operating temperature detectable as the fixed temperature type (a fixed temperature type thermostat) can be selected. The characteristics are depicted, as shown as a solid line in the diagram of FIG. 6.

I claim: A fire detection apparatus of the compensation type comprising a heat receiving shell,

a boundary plate secured to the open end of said heat receiving shell,

said heat receiving shell and said boundary plate being of thin sheet metal and having a high coefficient of linear expansion,

- the central part of said boundary plate having a cylindrical wall,

the latter being directed toward the inner surface of V the bottom of said heat receiving shell, 7

the lower end of said cylindrical wall being closed by adiaphragm, I 7

said heat receiving shell and, said boundary plate defining a heat receiving chamber,

a leak cylinder mounted on said boundary plate and providing communication between said heat receiving chamber. and the atmosphere,

a spring member fixed at one end to said boundary plate, I

oppositely disposed contacts provided on said diaphragm and, on a free end of said spring member,

said contacts being adapted to be connected with an electrical circuit of an alarm device,

an operating member of metal having a low coefficient of linear expansion mounted at both of its ends on said boundary plate,

said operating member being bent at its middle part extending across and above said free end of said spring member, and

an adjusting screw threaded through the middle part of said operating member and adapted to be contacted resiliently with the free end of said spring member.

References Cited by the Examiner UNITED STATES PATENTS 400,917 4/89 Iwanowski 200- 2,389,429 11/45 Griffith 200-440 FOREIGN PATENTS 934,635 10/55 Germany.

BERNARD A. GILHEANY, Primary Examiner. 

